2013 Chadwick Medal and Prize

Professor Jonathan Butterworth, University College London. For his pioneering experimental and phenomenological work in high energy particle physics, especially in the understanding of hadronic jets.

Jon Butterworth has made many key measurements of particle physics processes at colliders, particularly those concerning the strong interaction, the proton, and the photon, and more recently electroweak physics, at the HERA electron-proton collider (DESY) and the Large Hadron Collider (CERN).

He made the first measurements of the production of the hadronic “jets” produced when quarks and gluons scatter in photon-proton collisions, and was Physics Chair of the ZEUS experiment in 2003/2004. He led the first measurement of jets and dijets at the LHC. He coordinated the ATLAS “Standard Model” group for the first two years of data-taking, leading more than fifty papers to publication.

He has also made key phenomenological improvements related to the understanding of jets, including multiple-parton interactions, parton densities in the proton and photon, and the substructure of jets. These ideas, especially those on interrogating jet substructure, have been widely used in searches for physics beyond the Standard Model. For example, for the identification of highly boosted (as a result of being created at very high energies) decays of top quarks, jet substructure studies are essential because frequently the decay products of the top quarks all appear inside the same jet of hadrons. Identification of boosted Higgs bosons has also proved to be the most sensitive way of identifying Higgs decays to b-quarks. He has written several seminal phenomenology papers on these topics. He has also developed several software packages which are very widely used in the simulation, measurement and understanding of high-energy collider data. Butterworth has worked on design, construction and development of the ZEUS and ATLAS detectors and their upgrades, including leading the successful bids in the UK for a microvertex detector upgrade for the ZEUS detector, and the first stage of the ATLAS detector upgrades in the UK.

He is also a committed communicator to the public. He has appeared on Horizon and writes regularly for the Guardian.